#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <sys/socket.h>
#include <sys/wait.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#define MYPORT 3490
#define BACKLOG 100

#define BUFFLEN 4096

int main()
{
	int sockfd, new_fd;
	struct sockaddr_in my_addr;
	struct sockaddr_in their_addr;
	
	char rcv_buf[BUFFLEN];

	struct sockaddr_in addr;
	int addr_len;

	int sin_size;
	if ((sockfd = socket(AF_INET, SOCK_STREAM, 0)) == -1)
	{
		perror("socket");
		exit(1);
	}


	int on = 1;
	if(setsockopt( sockfd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on)) == -1){
		perror("setsockopt error:");
		exit(1);
	}
	my_addr.sin_family = AF_INET;
	my_addr.sin_port = htons(MYPORT);
	my_addr.sin_addr.s_addr = INADDR_ANY;
	bzero(&(my_addr.sin_zero),8);
	if (bind(sockfd, (struct sockaddr *)&my_addr, sizeof(struct sockaddr))== -1)
	{
		perror("bind");
		exit(1);
	}
	if (listen(sockfd, BACKLOG) == -1)
	{
		perror("listen");
		exit(1);
	}
	while(1) {
		sin_size = sizeof(struct sockaddr_in);
		if ((new_fd = accept(sockfd, (struct sockaddr *)&their_addr, &sin_size)) == -1)
		{
			perror("accept");
			continue;
		}
		
		//printf("server: got connection from %s\n", inet_ntoa(their_addr.sin_addr));
		if(getpeername(new_fd,(struct sockaddr*) &addr, &addr_len) == 0){
			printf("server: got connection from %s:%d\n", inet_ntoa(addr.sin_addr), ntohs(addr.sin_port));
		}

		if (!fork())
		{
			int len=0;
			if((len=recv(new_fd, rcv_buf, BUFFLEN,0) )> 0){
				rcv_buf[len]='\0';
				printf("server recv: %s\n", rcv_buf);
			}
			if (send(new_fd, "Hello, world!\n", 14, 0) == -1)
				perror("send");
			close(new_fd);
			exit(0);
		}
		close(new_fd);
		while(waitpid(-1,NULL,WNOHANG) > 0);
	}
	return 0;
}
